Brake shoe key



c. R. BUSCH BRAKE SHOE KEY Feb. 8, 1938.

2 Sheets-Sheet 1 Filed June 19, 1935 q l-l F WIN? q b Mi m mm INVENTOR ATTORN EY Feb. 8, 1938. j c. R. BUSCH 1 BRAKE SHOE KEY Filed June 19, 1935 2 Sheets-Sheet 2 in 0Q W n. l In I h m F I INVENTOR ATTORNEY Patented Feb. 8, 1938 BRAKE SHOE KEY Charies Prlsuseh, @range, N. l, assignor to Butfalo Brake Beam Compan a corporation of New York Application June 19, 1935, Serial No. 27,331

14 Claims.

The present invention embodies certain improvements in brake-shoe keys of the type shown, described and claimed in my previous applications Serial No. 550,661,'filed July 14, 1931 and Serial No. 619,472, filed June 27, 1932, which have matured respectively into Patent No. 2,328,753, dated January 28, 1.936 and Patent No. 2,013,981, dated September 10, 1935, and the principal object of the invention resides in so constructing the key, whether it comprises'a single length of spring metal or two connected lengths of spring metal, as to provide a non-vibrating or non-chattering and a self-locking key for holding brake shoes onto the brake-head, which key in use will not become dislocated upwardly from its proper locking posi tion, and will always act safely in spite of varying conditions in the key-way of the castings through which the key passes, as well as when wear has occurred between the castings caused by the action of the brakes and the vibration of he looked parts when other types of keys have been used.

The same being among the objects of the present invention, the invention consists of certain features of construction and combinations of parts, whether in the improved key itself or in a combination of the improved key with a shoe held thereby to a brake-head, to be hereinafter described and then claimed with reference to the accompanying drawings illustrating certain embodiments of the invention, and wherein Fig. 1 is a broken side elevation of a brakeshoe held on a brake-head by the improved key shown in Fig. 2;

Fig. 2 is a side elevation of the key shown in Fig. l which is a bifurcated or two legged key, showing the position of the parts of the key when not under pressure;

Fig. 3 is a front elevation of the key shown in Fig. 2;

Fig. 4 is a side elevation of a modified construction of key;

Fig. 5 is a side elevation of a second modification of the key;

Fig. 6 is a side elevation'of a third modification of the key;

Fig, 7 is a view similar to Fig. 1 but illustrating an improved key residing in a single length of spring metal; and

Figs. 8 and 9 are respectively a side elevation and a front elevation of the key of Fig. 7, but showing it in its free state and not under compression.

According to Figs. 1, 2, and 3 the brake-head I is provided in the usual manner with apertured front lugs or m 13 is provided y, New York, N. Y.,

embers H, [2, and the brake-shoe with the usual apertured lug or member M which is to set between the lugs i i I 2 when the brake-shoe is in head, so as to provide them for receiving a vention the key may proper position on the the usual key-way between key. Under the present inbe of the bifurcated type to comprise two legs l5, it of leaf-spring metal, the leg it being the front leg and the leg it the rear leg, and both with respect to legs being arranged breadthwise each other.

The front leg may be suitably shaped and constructed, but preferably it corresponds with the front leg shown, described and claimed in my application Ser ial No. 550,661, that is, the leg i5 is bent or deflected outwardly to provide a bearing portion l'l which deflection results in the provision of a shoulder I8 at one end of the bearing portion ii and a shoulder 19 at its other end. Furthermore, the spring metal strip or front leg i5 is provided with a front depression 20 which is defined by the aforesaid shoulder H9 at one end of the depression and by a shoulder 21 at the other end thereof located adjacent the lower end of the key.

When the key is bifurcated to provide two spring legs such as l5, It, the upper ends thereof are bent rearw ardly and suitably connected together to provide a driving or withdrawing lug 22 at the upper end of the key. 1 and 2, the upper ends of the legs may be connected together and combined in the manner shown, described and claimed in my application Serial No. 619,472, that is to say there is inserted between the upper ends of the legs, where they are of elbow shape, a suitable metal filler 22a constituting a spacer, the rearwardly directed parts of the lug 22 being connected together by a rivet 23, and the being connected together by a rivet 24, so that r parts directly below the lug 22 these parts at the upper end of the key are firmly and solidly united together.

The rear leg cipal improved i6 is provided with the prinfeature of the present invention and this resides in so curving or bowing the same for substantially its length rearwardly or outwardly away from the front leg l5 in such manner as to locate the greatest curvature, rearwardly, away from the lower part of the longitudinally extending front leg. This will portion of the rearward curve of the rear leg l6 bearing portion ll of the define a location of that with a curvature of the least radius, at points below the approxi is indicated by mate mid-length of the key which the line A-A in Fig. 2, for the the upper end of longated bearing portion l? of the front leg is.

each leg is purpose to beexplained. Such greatest curvature or curvature of least radius is-approximately indicated by the bracketed portion in Fig. 2. Furthermore, the rear leg bears at its lower end on the lower end of the front leg l5 and is preferably extended beyond the terminal of the front leg so as to provide a leader 28 to facilitate the insertion of the key into a key-way.

When a spring key such as shown in Figs. 2 and 3 is fully driven into the key-way of an assembled head H] and shoe 53 (Fig. 1) its driving lug or the like 22 is brought to bear upon the brake-head ill, the probrought to bear upon the inner surfaces of the lugs l l, l2, and the rear leg I5 is brought to bear upon the inner surface of the cross-piece lilo of the brake-shoe lug i l. The forcing of the spring key into the key-way therefore sets'the spring legs of the key in a state of compression between the interengaging lugs of the shoe and brake head and draws the shoe firmly uponthe brakehead.

As the maximum distance between the spring legs l5, it is greatest opposite the rearwardly curved portion 25 of the rear leg, and as therefore such extreme curved portion 25 is located below the shoe lug I l when the spring-key is in place, it will be understood that the effective locking of the key in the key-way is accomplished by such portion 25, inasmuch as to withdraw the key from the key-way considerable upward force must be used in order to compress the 'two legs together for a less'distance than that shown in Fig. l, as that get the curved portion is necessary in order to 25 of less radius from underneath the cross-piece l laof the shoe lug l4. 7 It has been found in practice that when the thickness of the leaf-spring metal of which composed is one-eighth of an inch and the breadth of each is seven-eighths of an inch, and the metal pro-perly tempered, the improved key locked in position as in Fig.1, will not move upwardly and tend to become detached or loose when such provision as the specially located curved portion 25 is inherent in the key. Practice has shown that the improved key is thoroughly efficient in service and usually maintains its locked position, although extra precaution may be provided by the forward shoulder 21 on the front leg and by the front depression 2i), although it would happen very seldom, if at all, that the improved key would be forced up far enough by vibration in order to locate the head-lug H! in the depression 23. It will be observed that while the improved key is resilient its effective stiffness or resistance against its dislocation or looseness is increased by the fact that the rear leg it not only has a bearing upon the rearwardly deflected portion at of the front leg, but also upon the terminal of the front leg.

In Fig. 4.- a modified construction of bifurcated spring key is illustrated, the front leg 21 and rear leg 28 being formed from one piece or strip of spring metal which is doubled or bent over at 29 and provided with a filler or spacer 36, the parts being solidly and firmly united together similarly to the construction in Fig. 2. The front 21 is similar to the previously described front leg, whereas the rear leg 28 is curved outwardly or rearwardly away from the front leg and is shorter than the front leg so that the front leg may bear upon the terminal of the rear leg and be extended to provide a leader St to facilitate the introduc- 0 tion of the key into a key-Way. The shorter leg the front leg-Fig. 4, isshown 28 is furthermore provided with the same improved feature as the key shown in Fig. 2, that is to say the short leg 28 is provided with a greater curvature or a curvature of least radius at 32 at points below the approximate mid-length of the key indicated at A--A. This key will. act similarly to the key in Fig. 2, except that the leader 3! is on the rear leg. There is also aforward shoulder 21a on the lower end of the front leg, inasmuch as the same as the front leg in Fig. 2. 1

It will be noted that in Fig. 4 the lower extremity of the shorter rear member or leg 28 extends into a concavity of the longer front memher or leg 2'! which is produced in the convex side thereof by reason of the forming of the shoulder or hump 21a on the concave side of the front ,member, and that the shorter member 28 there bears on the member 21.

In Fig. 5 a modification of what is shown in Fig. 2 is illustrated and the two keys are substantially the same, except that in Fig. 5Tthe front leg 33 is connected with the rear leg Sdby a loop 35, the entire key being composed of a single length of leaf-spring metal doubled and bent to the approximate shape shown, thus providing a driving or withdrawing loop 35 in the nature of a lug, but which has a certain amount of springiness within itself. In Fig. 5 the lower end of the front leg is suitably formed so as to provide an abrupt forward shoulder 330., such as shown specifically'in my application Serial No. 558,661. The rear spring leg 34 is formed similarly to the corresponding leg previously described, that is, along the length of its curve it is provided'with a more greatly curved portion 36 or portion having a curve of least radius, located at points below the approximate mid-lengthA-A. This key will also act similarly to the keys previously described.

Fig. 6 discloses a still further, modification wherein instead of making the connection between the two spring legs 31, 38 at the upper end of the key, that is at the driving lug portion,

7 the connection between the legs is provided by i a bend 39 at the lower ends of the legs, the key shown in Fig. 6 being formed from a single doubled length of leaf-spring metal, wherein the free ends of the legs are located at the upper end of the key. The upper end of the legB'i is bent rearwardly to provide a rearward portion 40 and the front leg 38 is bent rearwardly to provide a rearward portion 4|, such leg 38 also having a forwardly deflected portion 42. It will be seen that the forwardly deflected portion 42 bears upon a portion of thefront leg 3! and that the rearwardly bent portions 40, 4| bear upon each other, they constituting means for driving or withdrawing the key. When the key of Fig. 6 is introduced into a key-way of a brake-head and shoe it will act similarly to the previously described forms, except that in inserting the key the portions 4D, 4! will move relatively to each other with some friction.

Of course it is preferred that the spring key of Fig. 6 be provided along its rearwardly curved rear leg 38 with a' portion 53 of greater curvature, or a portion of least radius, located below the approximate mid-length A-A. g

It should be mentioned that while the line A-A in the already described figures is supposed to indicate the approximate mid-length of each key, transversely thereof, it more nearly represents that portion of each key which extends front leg instead of on the above the lower edge of the shoe lug when the key is in proper using position.

In Figs. '7, 8, and 9 the key instead of having two legs of leaf-spring metal is made of one length 44 of preferably leaf-spring metal formed and bent to substantially the shape in side elevation in Fig. 8; that is, the spring key when free from pressure will have a normal set substantially as shown at the upper end of key 44 as a rearwardly bent driving lug 45 and is substantially straight as shown at 46-for approximately onethird of the length of the key, the intermediate or'middle portion of the key being curved rearwardly, and the rearward curvature being such as 15 to locate the maximum curve or the curve of least radius along the bracketed portion 41, so that the portion 4'! is located below the approximate mid-length of the key indicated at 3-3. The lower portion 48 of the key 44 is deflected forwardly so that below the upper portion 46 of the key the remainder thereof is preferably formed on a compound curve, with the greatest rearward curvature approximately at 41.

' The spring key with a single length of spring metal should be thicker and stronger than the corresponding rear leg of the described bifurcated keys and the thickness may be one and one-half or twice that of the rear leg referred to. When the single leg key is driven into using position shown in Fig. 7, a part of its straight portion 46 will bear on the lug 5| of the brake head 50 and the key will also bear upon the lower portion of the cross-piece 54 of the shoe lug, the more prominent portion, that is to say the more greatly curved part of the key being positioned directly at and below the lower corner of the shoe lug 54, and furthermore the upper end 'of I the spring key 44 will bear upon the upper end of the brakehead 50 while the lower portion 48 of the key will bear forwardly upon a toe lug or cross-piece 55 upon the lower end of the brake head 50. Hence this modifi ed form of spring key will be in strong bearing relation with the upper and lower ends of the brake shoe head 50 and with the shoe lug 54, so as to firmly draw the shoe 53 up to the head 50. At the same time the portion 4! of the spring key 44 and which is of less radius than the general rearward curve of the key, will be positioned directly below the shoe lug 54, with the result that the vibration of the parts supporting the key will not dislodge the key from its locked position and the same will be held there until it is removed by suitable tools.

It will be seen from Figs. '7 and 8 that the illustrated key is provided with a forward shoulder 49 which interlocks under the toe lug 55 when the key is driven into place so that such engagement also may assist in preventing the key from moving upwards due to vibration of the parts.

Thefgreatest curvature or curvature which has least radius in the key and which is indicated at 25, 32, 36, 43, and ll in the various illustrated forms, when the key is applied to a brake head and a brake shoe, causes the key to act as a wedge member which exerts its greatest force below the brake shoe lug, which action is the reverse of that of the common standard type of brake shoe key, whose wedge member exerts its greatest force above the brake shoe lug, thus tending to release itself due to vibration. It is to be expected that such extreme curvatures, located as described and shown, will prevent the key from moving up during the travel of the train or car, but the lower forward shoulder shown and described is a definite measure of precaution against the jumping or moving up of the key when sudden shocks to a car truck or car are caused, as when dumping a load of coal or the like, for in such cases the sudden shocks cause the common standard type of brake shoe keys to be loosened and frequently to jump up so as to disconnect the brake shoes from their heads.

What I claim as new is:-

1. In combination, a brake head and a shoe having a key-way and inter-engaged apertured members, the apertures registering with one another, and a key in the key-way and passing through the apertures, and including two broad legs of spring metal relatively arranged breadthwise at different distances from the shoe, and means connecting the legs, the leg further from the shoe being so curved away from the other leg as to dispose its greatest curvature longitudinally of the key at points below the apertured member of the shoe.

2. In combination, a brake head and a shoe having a key-way and inter-engaged apertured members, the apertures registering with one another, and a key in the key-way and passing through the apertures, and including two broad legs of spring metal relatively arranged breadthwise at different distances from the shoe, and means connecting the legs, the leg further from the shoe being so curved away from the other leg as to dispose its greatest curvature longitudinally of the key at points below the apertured member of the shoe, and one of the spring legs having an outward shoulder located towards the lower end of such leg and beyond the apertured members.

3. A brake-shoe key, including two legs of leaf spring metal and means connecting the spring legs, one in front of the other, both legs curved in the same direction in the position which they occupy and the rear leg being so curved away from the other leg as to dispose its greatest curvature longitudinally of the key at points below the mid-length of the key.

4. A brake-shoe key, including two legs of leaf spring metal and means connecting the spring legs, one in front of the other, both legs curved in the same direction in the position which they occupy and the rear leg being so curved away from the other leg as to dispose its greatest curvature longitudinally of the key at points below the mid-length of the key, and one of the legs having at its outer in-curved side an outward shoulder located between the connecting and the free end of such leg.

5. A brake-shoe key, including two legs, each of leaf-spring metal and means connecting them, both legs curved in the same general direction in the position which they occupy, and the leg which is curved outwardly away from the other leg having a curve of less radius than the curve of such other leg, both legs being flexible from end to end, the radius of the curve of that leg which is of less radius having a curve of still less radius at points below the mid-length of the key.

6. A brake-shoe key, the same being formed from leaf-spring metal, and comprising two legs which are mutually opposed broadside, and means connecting corresponding ends of the legs and serving as means for driving or withdrawing the key, the terminal of the forward leg bearing upon the other leg, and the terminal of such other leg extending beyond the bearing point to form a leader.

7. A brake-shoe key, including two legs of leaf-spring metal and means connecting the having a, key-way and interengaging apertured' spring legs and holding them breadthwise one in advance of the other, the rear leg being so curved away from the other leg as to dispose its greatest curvature longitudinally of the key at points below the mid-length of the key, one of the leaflegs having an outward shoulder located between the connecting means and the free end of such leg.

I 8. Abrake-shoe key, including twovoppositely acting legs of spring metal connected together at one end of the key and free at the other end, one leg located in advance of the other leg, and

the other leg-bowed between its ends for a considerable part of its length relatively to and outwardly from the advance leg, the maximum distancebetween the two legs being the greatest below the approximate mid-lengths thereof.

In combination, a brake-head and a shoe members, the apertures registering with one another, and a key including a length of spring metal substantially co-extensive with the length 7 of the key-way and extending breadthwise of the apertures, and having an outward shoulder formed integrally therewith and located towards the lower end thereof beyond the apertured spring metal of such lugs and beyond them, and the key having an outward shoulder formed integrally theremembers, said key having engagement with a part of the head above the outward shoulder, such key being bent rearwardly on a curve which has its least radius at points below the midlength thereof and directly below that part of the key which bears on the apertured member of the shoe.

10. In combination, a brake-head and a shoe having interfitting attaching lugs provided with aligned openings, and a key for securing the shoe head and including a length of snugly on the I sumcient extent to pass through with and being "cent rearwardly on a curve which has its least radius at points below, the mid- 1 length of the key and above the shoulder, the

. upper end of the spring key being in bearing re= lation with the upper end of the brake-head and concavity.

the shoulder being in bearing relation with the lower end of the brake-hem.

11. A key for connecting brake shoes to brake heads and formed of strip metal comprising a long member and a resilient short member, said members being curved lengthwise and the short member being ofgreater curvature than the long member, said long member having towards its extremity a hump on its concaved side forming a concavity on its convex side, and the extremity of said short member terminating within said 7 12. A key heads, comprising a longmember and a resilient short member, said members being curved lengthwise and the short member being of greater curvature than the long member, said long memher having towards its extremity a bump on its 7 concaved side forming a concavity on its convexv side, and the extremity of said short member side, and the extremity of said short member terminating within said concavity, the radius of the curve of the shortmember being less at points below the midlength of the key.

14. brake-shoe key, as an article of 1118111 faoture, including a strip of spring metal of a length sufficient to pass through, and at both ends beyond, the connecting lugs of a brake-shoe and its supporting brake-head, and such a strip being preformed for insertion through such connecting lugs by being bent rearwardly on a curve whichin the-using position of the key'will be directed towards that surface of the shoe lug whereon the strip will ultimately bear,'and which curve has its leastradius at points directly below that part of the strip which is to ultimately bear on the lug of the brake shOe.

CHARLES R. BUSCH.

for connecting brake shoes to brake V 

